using python how to give 0, 1 , 2 for ternary variables?

Question

I have csv file, with column names of: PH, K, Zn, S, Fe ...so on. For each column there hare 3 different types of output, for example:

PH       S       Zn     Fe         Cu   Mn
Acidic   Low    Low     Medium  High    Medium
Alkaline High   Medium  Medium  High    High
Acidic  Medium  Low     Medium  High    High
Neutral High    Low     Medium  High    High
Acidic   Low    Low     Medium  High    High
Acidic   Low    Low     Medium  High    High
Acidic  Medium  Medium  Medium  High    High

I want to give values of

Acidic = 0, Neutral = 1, Alkaline = 2
Low = 0, Medium = 1, High = 2

How to write a code which is automatic convert Acidic=0 , Neutral=1 , Alkaline=2?

@CedricDruck, Oh, Okay, How to convert Low, Medium, High in terms of 0, 1, 2 ? is it possible? — Kiran Prajapati, Feb 20 '17 at 06:46
I'd use dicts .. something like ph_dict = {'Acidic': 1, 'Neutral': 2, 'Alkaline': 3} — Cedric Druck, Feb 20 '17 at 06:47
If you are working on some machine learning tasks and are using a library for that, `scikit-learn` and `pandas` have some inbuild functions for doing that. — Vivek Kumar, Feb 20 '17 at 07:07
@VivekKumar, yes I am working on same machine learning tasks, and using scikit-learn and pandas. but, I want specific numbers for acidic = 1 , neutral = 2 so on , so I am confuse — Kiran Prajapati, Feb 20 '17 at 07:09

score 3 · Answer 1 · answered Feb 20 '17 at 07:15

3

Ok so something like

dicts = {
   'PH' : {'Acidic': 0, 'Alkaline': 1, 'Neutral': 2},
   'S': {'Low': 0, 'High': 1, 'Medium': 2},
   # etc
} 
with open(your_file) as file:
    table = []
    reader = csv.DictReader(file)
    for row in reader:
        new_row = {key: dicts[key][value] for (key, value) in row.items()}
        table.append(new_row)

answered Feb 20 '17 at 07:15

Cedric Druck

1,032
7
20

Yes, that's actual Python code .. what's the question? – Cedric Druck Feb 20 '17 at 07:26
your_file means my file name is samplefile.csv so i have use with open (samplefile.csv) as file : ? – Kiran Prajapati Feb 20 '17 at 07:27
you have to use some sort of path to your file, yes. See https://docs.python.org/2/tutorial/inputoutput.html#methods-of-file-objects – Cedric Druck Feb 20 '17 at 07:28
and reader = csv.DictReader(file) so, here I have use file or something my path ? – Kiran Prajapati Feb 20 '17 at 07:29
no, file is the result of open(your_file), you just have to adapt the "your_file" variable – Cedric Druck Feb 20 '17 at 07:29
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/136128/discussion-between-kiran-prajapati-and-cedric-druck). – Kiran Prajapati Feb 20 '17 at 07:31

score 1 · Answer 2 · edited May 23 '17 at 11:46

1

Python provides the Enum class. Why you want to use Enums is covered here. In your case they would look something like:

Code:

from enum import Enum
PH = Enum('PH', 'Acidic Neutral Alkaline')
Concentration = Enum('Concentration', 'Low Medium High')

Demo Code:

print(PH['Acidic'].value)
print(Concentration['Medium'].value)

Produces:

1
2

Demo Code2:

for i in range(1, 4):
    ph = PH(i)
    concentration = Concentration(i)
    print(ph, ph.name, ph.value)
    print(concentration, concentration.name, concentration.value)

Produces:

PH.Acidic Acidic 1
Concentration.Low Low 1
PH.Neutral Neutral 2
Concentration.Medium Medium 2
PH.Alkaline Alkaline 3
Concentration.High High 3

edited May 23 '17 at 11:46

Community

1
1

answered Feb 20 '17 at 07:13

Stephen Rauch

47,830
31
106
135

Can I use 1,2,3, numbers output for my next analysis using enum? – Kiran Prajapati Feb 20 '17 at 07:20
1

Yes, the `value` is a number, see examples. – Stephen Rauch Feb 20 '17 at 07:22

using python how to give 0, 1 , 2 for ternary variables?

2 Answers2